Nothing fazes the world's top-ranked player these days, though. Fog had rolled in off Great Peconic Bay, and the horn sounded with Park's group on the 18th fairway. The threesome finished out the second round of the U.S. Women's Open, with Park calmly sinking a birdie putt from 12 feet to move closer to history.

She shot a 4-under 68 on Friday for a 9-under total to lead fellow South Korean I.K. Kim by two strokes. Park is seeking to win the year's first three major championships; no one has accomplished that feat in a season with at least four majors.

Of the players yet to finish the round, the closest, England's Jodi Ewart Shadoff, was five strokes back with three holes to go.

Ha-Neul Kim, the first-round leader, had a 77 to fall to 1 under.

Players were surprised Thursday to arrive at Sebonack to find the tees moved up and the weather calm — an easy course by U.S. Women's Open standards. On Friday, the setup and the conditions were more what they expected: The wind picked up and some pins were tucked into uncomfortable spots.

Then the mist settled in late in the afternoon session.

Of the 114 players who finished, only nine were under par for the round.

"With the wind and fog, it really made me think that's what the U.S. Open is all about," said Park, a five-time winner this year coming off consecutive victories.

Of the other players to complete the round, Lizette Salas was third at 4 under after a 72. Fellow Americans Angela Stanford and Jessica Korda were another stroke back. Stanford had a 68, and Korda shot 71.

I.K. Kim shot a 69 in the morning session.

"Anything under par I thought was going to be a great score," she said.

Kim seems to thrive under the demands of this tournament, finishing in third or fourth place three straight years from 2008 to '10.

But the closest she came to a major title came last year at the Kraft Nabisco — one foot away, to be exact. Needing just a short putt to clinch the championship, Kim watched the ball lip out on the 18th hole. She went on to lose in a playoff.

"Everybody has ups and downs," Kim said. "Definitely finishing top five in the U.S. Open is not a bad place. But there's times that I was disappointed. I just have a faith — if you do your best, everything is going to be OK."

Park's putting was not quite as impeccable as usual, but she made one of her toughest birdie tries of the day on No. 13, a 20-footer from the fringe, to tie Kim at 7 under.

On the par-5 15th, she sent her third shot to the back of the green, where it bounced off the fringe and rolled down to within a foot of the hole. Park tapped in for birdie and the outright lead.

"Everything that was closer was not going in, then everything that was further away from the hole was going in today," she said. "It was weird."